1. Field of the Invention
The present invention relates to a hand-held copying apparatus.
2. Description of the Prior Art
As disclosed in Japanese Patent Laid-Open No. 115773/1980, there is proposed a copying apparatus which is enclosed in one case as a whole. A reading window is set on a lower surface portion at the center of a body, which has a problem that an image on a marginal portion near a book binding cannot be read thoroughly.
Then in the case of a hand-held recording apparatus, images and characters are recorded at a predetermined moving rate by moving the apparatus manually in the direction intersecting longitudinally with a recording head incorporated therein. However, in a conventional recording apparatus of this kind, the thermal head used particularly for a recording head must be kept in contact with a surface to be recorded (or recording paper). Therefore the head is left protruding downward (toward a body) at all times, and may sustain damage to an important heating element provided on its tip, ribbon is also exposed at the tip, which may incur damage at the same time.
On the other hand, in a conventional thermal printer of manual scanning type which is placed on a recording paper and scanned (sub-scanned) by hand for recording characters or pictures on the recording paper, the width of a driving pulse for heating the thermal head and a voltage therefor are set to constant values. When scanning at a rate exceeding a normal range, the pulse duty cycle is raised, the thermal head is driven for recording the next data before it radiates heat completely, i.e., heat is accumulated, and thus the printed dots become large or the printing density becomes thick resulting in deterioration of the print quality. A relation between a scanning rate pulse A from an encoder and a head driving pulse B' is shown in FIGS. 22(a) and 22(b). In this case, the width of the pulse B' is constant, however, in the case of high-speed scanning, the pulse duty cycle becomes excessively high.
On the other hand, in a thermal printer feeding a recording paper automatically, deterioration of the print quality is prevented by detecting a temperature of the thermal head and controlling the driving pulse width according to the detected result. However, the system will entail a delay in thermal conduction, and for avoiding the delay an extremely small sensor must be provided near the heating element, which is problematical in workability and cost.
Then, in the case of a recording head incorporated in a hand-held recording apparatus moved by hand for recording on a paper, the head front must be applied correctly to a reference plane of the apparatus corresponding to a surface of the recording paper. The structure for pressing the head evenly with a spring has been rather complicated.